(a) Field of the Invention
The present invention relates to an improved structure of a vertical-type acid and base resistance pump, and in particular, a pump having a shaft cap mounted with seals contacting with the ceramic ring mounted to the pump.
(b) Description of the Prior Art
FIGS. 1 and 2 show a conventional pump essentially comprising a motor 10, a seal cap 2, a shaft cap 3, a seal 31, a body 4, a propelled wheel 32, an outlet tube 41. The front section 10 is mounted with a shaft center 1 and the external of the shaft center 1 is provided with the body 4. The bottom of the body 4 is provided with the outlet tube 41 allowing fluid to enter and leave the pump. The shaft center 1 is mounted with the shaft cap 3 and the bottom thereof is connected to the propeller wheel 32 having tubular shape front.
The front section of the motor 10 and the top section of the body 4 are provided with the seal cap 2. The interior of the seal cap 2 is ejection molded to form a ceramic ring 21. The seal 3 located at the bottom of the ceramic ring 21 is provided with a dry-type seal 31. If the pump is not in operation, the seal 31 moves upward and in contact with the bottom of the ceramic ring 21 at the seal cap 2. When the pump is in operation, the centrifugal force causes the moving plate of the seal 31, which in contact with the bottom of the ceramic ring 21 at the side thereof is disengaged. Due to the poor design of the seal, only when pump is not running, acidic gas can be prevented from entering the pump (as shown in FIG. 3), but the pressure of the reverse flow of the fluid cannot be prevented. In this conventional structure, when the shaft center 1 of the motor rotates, (the suction of vacuum show in FIG. 4), the external air will enter the pump through the slit (as shown by the arrows) between the shaft cap 3 and the pump 4 of the motor 10 as a result of vacuum suction and the rotation of the motor 10, such that the vacuum provided by the pump is greatly reduced. Due to the insufficient of the vacuum, and there is only one seal 31 with the moving plate, the sealing is insufficient and it cannot withstand the pressure caused by the reverse flow of the corrosive fluid.
Further, the leakage proof is insufficient (refer to FIG. 3). to withstand the prolong abrasion of the ceramic ring 21 with the seal 31, When the pump is not in operation, the fluid at the outlet tube 41 will overflow the seal 31 which Other damages the seal at the front cover of the motor. In addition, the fluid, that overflow will pollute the environment. Accordingly, it is an object to provide an improved structure of a vertical-type, acid and base resistance pump wherein the above drawbacks such as poor vacuum and fluid overflow, can be overcome.
Accordingly, it is an object of the present invention is to provide an improved structure of a vertical-type, acid and base resistance pump, which mitigates the drawbacks of the conventional structure of a pump.
Yet another object of the present invention is to provide an improved structure of a vertical-type, acid and base resistance pump, wherein the pump is acid and base resistance, and gas is prevented from entering into the pump, and fluid is prevented from reverse-flowing into the pump, thereby vacuum within the pump is improved.
A further object of the present invention is to provide an improved structure of a vertical-type, acid and base resistance pump, wherein the pump is avoided from contamination and the motor of the pump is prevented from damaging, and thereby the longevity of the pump is prolonged.
An aspect of the present invention is to provide an improved structure of a pump comprising a motor, a seal cap, a ceramic ring, two seals, a shaft cap, a propeller wheel and a pump body, the front of the motor provided with a shaft center having mounted with the shaft cap to prevent fluid from entering the pump and to engage with the propeller wheel, the external side of the shaft center provided with the pump body having an outlet tube, the seal cap located between the top section of the body and the motor, and the bottom section of the body mounted with the ceramic ring, characterized in that the positive face and the reverse face of the shaft cap are provided with the high abrasive resistance seals, and the two seals are in contact at the top and bottom of the ceramic ring such that gases will not be absorbed by the pump, and no overflow of fluid in the course of shutting down or starting-up of pump.
Other object and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawing.